Recent improvements in multiple access methods allow contending end-user devices access to shared networking resources in an orderly fashion. With the advent of wireless communication networks, many access methods have become unsuitable for allocating shared resources. In particular, the different types of traffic and differing Quality of Service (QoS) requirements of each user can dramatically affect the signal quality (i.e. SNR) achieved by each user. With the diversity of applications which can be made available over a communication network, the problem of assignment of shared resources based on the QoS required by each end-user and the efficient use of bandwidth in a practical communication system become increasingly important. The disadvantages of the existing systems become more acute in mobile wireless communications systems, between a mobile end-user and a base station, especially when an integrated mix of traffic such as speech, audio-visual and data communications are supported in the same channels. The QoS requirements of each end-user may vary dramatically during an established call and the type of traffic between end-users and base stations may vary dynamically.
U.S. Pat. No. 5,751,708 by Mark J. Karol and Kai Y. Eng, and paper “Distributed-Queueing (sic) Request Update Mulitiple Access (DQRUMA) for Wireless Packet (ATM) Networks” by Mark J. Karol, Zhao Liu and Kai Y. Eng., IEEE International Conference on Communications 18-22 June 1995, ICC'95 Seattle, Gateway to Globalization, pages 1224-1231, describe an access method that allows an end-user device to piggyback, with a packet transmission, requests for access to a shared communications resource.
U.S. Pat. No. 5,598,417 A describes a TDM (time division multiplex) wireless communication systems where the only resource is a time slot. The system confines the communication services to two groups. One group deals with voice calls, circuit data connections, and system control information which are transmitted one slot per frame (a frame consists of a number of slots). The other group deals with packet switched data, which is transmitted in the rest of the slots of the frame. The system achieves a flexible transmission rate for a certain service only by allocating different number of slots per frame.
U.S. Pat. No. 5,572,546 describes a random access protocol, which is equivalent to slotted ALOHA and assumes that all terminals are able to listen to each other. This system is inherently unsuitable for mobile cellular system where the mobile terminals can only listen to base stations. The application of the protocol is mainly in multihop modems and coaxial cables.